The quality and scale is just not there yet.
"The concept of mass producing goods half way around the world and then shipping them is inherently inefficient."
I currently disagree with the above statement.
While I can make a plastic comb or hair brush, or some stupid little broken part of some appliance, I still can't 3D print the thing for less than buying it online or from a store. Not even close.
What I can do is play. I can test designs on the front end to determine what will be sent into production.
Cutting the cost of design/testing will have a huge impact on the front end and will lead to truly innovative products, but it can't match the efficiency of mass production.
Actually, many companies do manufacture regionally as close to the market as is feasible. I worked at a large mold shop awhile ago...we were working on the injection molds for the Gillette Mach 3 Razor....built several identical molds, including the molding machines, in individual units. Shipped each tool to a different continent, where the razors were actually produced. Shipping of the product was not eliminated, but the process was a lot more efficient than shipping overseas from one source.